In 2020, NTU used orange peel to recycle spent lithium-ion batteries; the process recovered about 90% of c

In 2020, researchers at Nanyang Technological University (NTU) in Singapore demonstrated a novel method using orange peel extract to recover 90% of cobalt, lithium, nickel, and manganese from spent lithium-ion batteries.

This bio-waste-derived technique challenges conventional pyrometallurgical and hydrometallurgical recycling processes by offering a more environmentally benign and potentially more economical alternative for critical metal recovery, directly impacting e-waste handlers and battery recyclers.

Citrus-Derived Solvents Revolutionize Battery Recycling Chemistry

The NTU team, led by Assistant Professor Dalton Tay, developed a process that employs a solution derived from orange peel, specifically containing citric acid and antioxidants, as a leaching agent. This replaces harsher chemical solvents typically used in hydrometallurgy, such as sulfuric acid, which require significant energy input and generate hazardous byproducts.

• The process achieved 90% recovery efficiency for cobalt, lithium, nickel, and manganese.
• Orange peel waste is a readily available, low-cost feedstock, reducing operational expenses for recyclers.
• The method operates at lower temperatures and pressures compared to traditional hydrometallurgical routes.
• It minimizes the generation of secondary pollutants, addressing a key environmental challenge in battery recycling.
• The recovered metals exhibited purity levels suitable for direct reuse in new battery manufacturing.

Economic and Environmental Advantages for Recyclers

This orange peel-based method offers significant advantages. From an economic standpoint, the primary reagent is a waste product, substantially reducing material costs compared to virgin chemical inputs. Environmentally, the reduction in strong acid use and the lower energy footprint translate to a smaller carbon impact and fewer regulatory hurdles related to hazardous waste disposal. This makes the NTU approach particularly attractive for smaller to medium-sized recycling operations seeking to improve their sustainability profile and reduce compliance costs. It also opens pathways for regional processing facilities closer to waste streams, reducing logistics overhead.

What This Means for Recyclers

E-waste and battery recyclers should monitor the commercialization of bio-leaching technologies like the NTU orange peel method. Integration into existing hydrometallurgical lines could significantly lower operational costs and improve environmental performance, offering a competitive edge. Operators should evaluate the scalability, throughput, and long-term stability of such bio-based reagents as they move from laboratory to industrial application. This signals a shift towards more circular and sustainable practices in critical metal recovery, potentially redefining best available technologies.